In computer networks, it is often desirable to detect intrusion or unauthorized access to a physical layer (e.g., a physical link, cable, or medium). For example, in an optical network, an optical cable between two network nodes may be vulnerable to unauthorized taps or other devices that can intercept, copy, or redirect packets. Existing techniques for detecting physical link intrusions are generally expensive and/or cumbersome. For example, one technique involves placing a physical link (e.g., a fiber or electrical cable) in a pressurized tube, placing pressure sensors along the pressurized tube, and detecting whether the pressurized tube changes pressure. In this example, it is assumed that an intruder trying to access the physical link will puncture the pressurized tube thereby altering the pressure in the pressurized tube. However, the technique is quite costly, and the nature of the pressurization loss is binary in that it merely shows a breach is occurring. There is no gradient. Another technique involves using a time domain reflectometer on the physical link, but this technique is also costly and cumbersome, and can show false positives, making monitoring challenging.
Accordingly, there exists a need for improved methods, systems, and computer readable media for detecting physical link intrusions.